There is a long felt need for gelled products in the personal care market. Gels allow for application to the skin of cosmetically elegant materials that provide benefit to the skin.
One example of the use of gels is the jellification of cyclomethicone with a combination of water and water-soluble dimethicone copolyol materials. The gel is used to deliver antiperspirant actives to the sin in a dry feeling system. Typical of the technology is U.S. Pat. No. 5,623,017, issued Apr. 22, 1997 to Hill, entitled Clear silicone gels describes “a method of forming a thermodynamically stable transparent product by combining (i) water; (ii) a volatile cyclic methyl siloxane or volatile linear methyl siloxane; and (iii) a silicone polyether surfactant.” This patent exemplifies the approach that has been taken to make gels of cyclomethicone for use in personal care products. The patent is related to thickening cyclomethicone, not esters with water (which is absent in the present invention), with an ethoxylated silicone. In short the art teaches that there is a long felt need to make gels in the personal care industry.
Those materials that are clear in the solvent generally define the Concept of what is soluble. Sodium Chloride is soluble in water. That is it is clear, but is also uniformly distributed in the solution. Unlike sodium chloride, which makes a uniform concentration solvent, materials that are bipolar are clear in water, but do not have uniform distribution in the solvent. The common example is sodium lauryl sulfate (SLS). SLS has a water-soluble sulfate group and an oil soluble lauryl portion (C12 hydrophobe). When SLS is added to water it is clear and consequently soluble. However, the molecule accumulates at the surface, lowering the surface tension. At a concentration called the CMC (critical micelle concentration) agglomerates form. SLS has an oil soluble and water-soluble group as shown below:CH3(CH2)11—SO4−Na+Oil Soluble|Water soluble
We have surprisingly found that in a way analogous to water based systems; ester based systems (oil loving), into which specific fatty esters are introduced are soluble (form clear solutions) but at concentrations above their cmc (critical micelle concentration) form a solid matrix at low concentrations. (a gel), by gel is meant a soft solid material that spreads under pressure.
Compounds useful for gelation of the esters described herein conform to the following structure:R—O—C(O)R′wherein
R is alkyl having 30 to 50 carbon atoms;
R′ is alkyl having 17 to 21 carbon atoms.
The specific compounds of the present invention when added at less than 10% to the specified esters provide a solid spreadable composition that is the topic of the present invention. These materials are buttery in feel and aesthetically appealing on the hair or skin.
The compositions of the present invention are oil soluble esters that are modified to have unique skin spreadability properties. This provides particular value in the personal care arena. Specifically, the ester based structured gels are useful as a carrier in antiperspirants, pigmented products, skin care products, and the like since they spread rapidly and efficiently on the skin from a stiff gel providing emmoliency and a host of ester soluble additives including sun screen actives, hydroxy acids, antioxidants, flavonoids, tocopherol, vitamins and the like. The gels are very cosmetically appealing having a dry feel on the skin and provide a lubricious property which improve the properties of skin creams, skin care lotions, moisturizers, facial treatments such as acne or wrinkle removers, personal and facial cleansers, liquid soaps, bath oils, perfumes, colognes, sachets, sunscreens, pre-shave and after-shave lotions, shaving soaps, and shaving lathers. It can be used in hair shampoos, hair conditioners, hair sprays, mousses, permanents, depilatories, and cuticle coats, to enhance cosmetic elegance.
In cosmetics, the compositions of the present invention will function as a leveling and spreading agent for pigments in make-ups, color cosmetics, foundations, blushes, lipsticks, lip balms, eyeliners, mascaras, oil removers, color cosmetic removers, and powders. It is also useful as a delivery system for oil and water-soluble substances such as vitamins. When incorporated into sticks, other gels, lotions, aerosols, and roll-ons, the compositions of the present invention impart a silky-smooth feeling, an outstanding payout.